I've had a lot of fun with my recently purchased GSG-16. It's unfortunately somewhat painful to break down, so I wanted to stick it in a rotating vise for easy access/positioning.
It turns out the GSG-16 isn't popular enough for anyone to sell locking magwell vise blocks. On the upside, this served as an excuse to get cozy with SolveSpace, a very cool parametric CAD program I've been wanting to learn. And it's FOSS
The image above is an auto-generated (!) view from SolveSpace. I guess it shouldn't be surprising that parametric design tools can emit these drawings on the fly, but I still think it's cool. Below you'll find a few pictures of the final product, and finally the stl.
File download here